In Europe, terrestrial television is currently broadcast in the UHF band in the frequency range 470 – 862 MHz. As a result of spectrum efficiencies brought about by the switch to digital broadcasting, in the next few years across Europe the frequency range 790 – 862 MHz will be cleared of broadcast use to enable new mobile services to be offered. The spectrum will be auctioned without specifying the technology to be employed. The major use is expected to be Long Term Evolution (LTE) – the fourth generation mobile phone system that will in addition bring broadband services to some rural areas for the first time, although other technologies could also make an appearance.
Although there will be no frequency conflict with off-air broadcasts, the current design of TV tuners will still be sensitive to signals in that range, and the cable TV networks will continue to use these frequencies for their services after the switch-over to mobile use. It is recognised that the higher field strengths created by these new mobiles in close proximity to TV sets and cable boxes have significant potential to cause interference.
Over the past six months, the European electrotechnical standards body, CENELEC, and the European Telecommunications Standards Institute (ETSI) have been working to define the nature of the expected problems and make recommendations for changes to standards, and for mitigation measures for currently available broadcast and cable TV receivers.
CENELEC will be holding a meeting of its EMC committee, TC210, together with its committee for cable TV networks, TC209, in Dublin, Ireland, on 12 and 13 August 2010 to plan the work needed to make the necessary changes to the standards. Changes to the European harmonised standards in these fields can be expected in the near future.
Brian Jones is an independent EMC Consultant, specializing in compliance with European legislation and standards. He is also secretary to the CENELEC EMC committee TC210, but is writing here in a personal capacity, and his views do not necessarily reflect the views of any organization. He may be contacted at emc@brianjones.co.uk
